The present invention relates to a system and method for preventing penetration to a secure area and, more particularly, to a system that automatically and reactively opposes such penetration.
Many methods are known for designing enclosures, such as safes and secure rooms, in a way that inhibits their penetration by intruders. Generally, these designs rely on passive inhibition of penetration. Representative components of passively protective enclosure walls include tough internal elements such as alloyed, hardened or carburized steel, or pieces of a ceramic such as carborundum, intended to obstruct drilling; bound elements such as combined metals, various types of concrete, etc.; materials of high thermal conductivity, such as aluminum or copper, intended to resist thermal break-in by conducting the heat awayxe2x80x94for example, aluminum or copper fins that conduct the heat to the inner surface of the wallxe2x80x94and thereby not allow the temperature to reach the melting point; and heat-insulating materials. Representative patents in the field include U.S. Pat. Nos. 4,505,208 and 4,765,254, to Goldman; U.S. Pat. No. 4,696,250, to Maxeiner; German Patent No. 25 25 738, to Danzer; and German Patent No. 44 15 986, to Leine et al.
German Patent No. 28 21 281, to Bardehle et al., discloses a safe wall with explosive pellets placed inside and intended to explode in case of an attempted break-in. This design has the advantage over the traditional passive designs that it is reactive. It has the disadvantage, in most civilian applications, of possibly injuring the intruder and damaging the surrounding property in the course of deterring penetration.
There is thus a widely recognized need, and it would be highly advantageous to have, a reactive barrier to penetration that does not suffer from the disadvantages of presently known systems.
According to the present invention there is provided a barrier resistant to penetration by a burglary tool comprising: (a) a rigid housing; and (b) a mechanism for mechanically trapping the foreign object, enclosed within the housing.
According to the present invention there is provided a method of inhibiting penetration of a secured space by a burglary tool applied substantially perpendicular to its direction of penetration comprising the step of automatically applying a lateral compressive force to the burglary tool, thereby trapping the burglary tool.
The principle of the present invention is illustrated in FIG. 1. A rigid housing 10 is penetrated by a foreign object 12 such as a cutting tool. Housing 10 contains a mechanism for exerting a lateral pre-compressive force on burglary tool 12. This lateral compressive force is represented in FIG. 1 by arrows 14. The lateral compressive force traps burglary tool 12, and stops its motion, thus making it difficult for the intruder to either penetrate further into housing 10 or withdraw burglary tool 12 from housing 10. For reference in the description below, double headed arrow 16 defines the longitudinal direction with respect to housing 10.
Typically, housing 10 is a steel tube sealed at both ends. Devices of the type illustrated in FIG. 1 may be used as such, for example as bars of prison cells. In most applications, however, an array of devices of the type illustrated in FIG. 1 is included in a wall, along with some of the conventional, passive anti-penetration systems described above. Because these devices are not used alone in most applications, they are referred to herein as xe2x80x9cbarrier componentsxe2x80x9d.
An important aspect of the present invention is the optional reliance on the xe2x80x9cshape memoryxe2x80x9d property of certain alloys. Most elastic materials, when subjected to a stress that exceeds their elastic limits, do not return to their original dimensions and shape. Some alloys, that exhibit the shape memory property, can be restored to their original shape by heating. Many of these alloys are characterized by a martensitic phase transition at a certain transition temperature. Examples of such alloys include titanium-nickel, iron-manganese, titanium-nickel-palladium, copper-aluminum-zinc and copper-aluminum-nickel. Alloys of this type, for industrial applications, are produced, for example, by Special Metals Corp. of New Hartford N.Y.